Added:

 * DM (Dream Maker) language.
 * Sample DM file.

The DM language is used in an engine known as BYOND which allows users to easily create their own games in a language that is designed to be accessible for newcomers. I do not know how much a language has to be used on the site to be considered but searching for "BYOND" does show a lot of people using the language. I am also still learning git so if I have missed something then please let me know.
 - Updated sample file.
 * Fixed a mis-formating.
 * Missed setting the lexer to Text Only.
 - Moving diff to after DM.
 * Trying this.
Merge pull request #450 from Giacom/master

Added DM (Dream Maker) language.